tcpcon.c

来自「TCP-IP红宝书源代码」· C语言 代码 · 共 46 行

/* tcpcon.c - tcpcon */

#include <conf.h>
#include <kernel.h>
#include <network.h>

/*------------------------------------------------------------------------
 *  tcpcon - initiate a connection
 *------------------------------------------------------------------------
 */
int
tcpcon(struct tcb *ptcb)
{
	struct	netif	*pni = ptcb->tcb_pni;
	struct	route	*prt;
	Bool		local;
	int		error, mss;

	prt = (struct route *)rtget(ptcb->tcb_rip, RTF_REMOTE);
	local = prt && prt->rt_metric == 0;
	rtfree(prt);
	if (local)
		mss = ptcb->tcb_pni->ni_mtu-IPMHLEN-TCPMHLEN;
	else
		mss = 536;			/* RFC 1122 		*/
	ptcb->tcb_smss = mss;			/* default		*/
	ptcb->tcb_rmss = ptcb->tcb_smss;
	ptcb->tcb_swindow = ptcb->tcb_smss;	/* conservative		*/
	ptcb->tcb_cwnd = ptcb->tcb_smss;	/* 1 segment		*/
	ptcb->tcb_ssthresh = 65535;		/* IP Max window size	*/
	ptcb->tcb_rnext = 0;
	ptcb->tcb_finseq = 0;
	ptcb->tcb_pushseq = 0;
	ptcb->tcb_flags = TCBF_NEEDOUT|TCBF_FIRSTSEND;
	ptcb->tcb_ostate = TCPO_IDLE;
	ptcb->tcb_state = TCPS_SYNSENT;
	tcpkick(ptcb);
	ptcb->tcb_listenq = SYSERR;
	TcpActiveOpens++;
	signal(ptcb->tcb_mutex);
	wait(ptcb->tcb_ocsem);
	if (error = ptcb->tcb_error)
		tcbdealloc(ptcb);
	return error;			/* usually 0 */
}